| 1. | Lubricant used for ball gearing is usually ? | |
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graphite
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grease
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mineral oil
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molasses
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Report Question| 2. | Insertion of reactance in the rotor circuit ? | |
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reduces starting torque as well as maximum torque
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increases starting torque as well as maximum torque
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increases starting torque but maximum torque remains unchanged
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increases starting torque but maximum torque decreases
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| 3. | In a star-delta starter of an Induction motor ? | |
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resistance is inserted in the stator
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reduced voltage is applied to the stator
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resistance is inserted in the rotor circuit
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applied voltage per stator phase is 57.7% of the line voltage
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| 4. | A 3-phase slip-ring induction motor is always started with ? | |
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a starting winding
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squirrel cage winding
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no external resistance in rotor circuit
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full external resistance in rotor circuit
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| 5. | A pump induction motor is switched on to a supply. 25 percent lower than its rated voltage. The pump runs eventually ? | |
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the pump will get heated and consequently get damaged
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the pump will stall after sometimes
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the pump will continue to run at lower speed without damage
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none
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| 6. | The A.C. motor which would be best suited to drive a centrifugal pump for discharging a variable quantity of water against a fixed head is the ? | |
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repulsion motor
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synchronous motor
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squirrel cage
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slip ring induction motor
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| 7. | A wound rotor induction motor is usually not selected when ? | |
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variable speed operation is desired
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cost is the main consideration
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high starting torque is the main consideration
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external voltage is to be fed into rotor
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| 8. | The possible number of different speeds that can be obtained by connecting two motors in cascade is ? | |
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2
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4
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6
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12
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| 9. | If an induction motor is to be run on unbalanced supply, then it should be run at ? | |
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lower loads
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low speeds
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higher loads
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higher speeds
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| 10. | Slip ring motor is recommended where ? | |
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speed control is required
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frequent starting, stopping and reversing is required
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high starting torque is needed
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all above features are required
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